MONEY TROUBLE

 

Objective:  Develop a system of equations to solve a problem.

 

Joe had a garage sale.  Joe’s sons, Chip and Skip, wanted to help count the money.  Joe let them count the change.  By careful pricing the change bin only contains dimes and quarters.  Unfortunately Chip and Skip took their father literally and counted the number of coins.  Chip counted 183 coins and Skip counted 103 coins.  Skip and Chip then dumped all their coins into one container and gave them back to their father.   Help Joe, chip, and Skip determine how much money they have without recounting the change.

                  

Equipment:      

 

  1. Scale
  2.  Bins containing dimes and quarters. 

 

Procedure:

 

  1. Each group is given a bin containing dimes and quarters. 
  2. Students find the mass of the bin.
  3. Students find the mass of a dime and a quarter.
  4. Set up a system of equations that will allow you to determine the number of dimes and numbers of quarters in the bin.  Compute the total value.

 

Variations:

 

  1. Have one class bin.  Give the groups the number and the weight and have a contest to see which group can find the value first.
  2. Give the students the number of each type of coin and have them compute the masses.
  3. Finding the mass of a dime and a quarter can be left as a research exercise or may be given to the students.
  4. Each group may be given their own bin.
  5. Use nickels and pennies if the value of the coins is a concern.
  6. I have seen similar projects using nuts and bolts but I think students would find money more interesting.

 

Teacher notes:

 

  1. Dime is 2.27 grams and quarter is 5.67grams.  You may provide these numbers or leave as a research exercise.   You may want to check this on the scale you use.
  2.  You generally will not get the exact number of dimes and quarters.  Have students estimate the value of the change.  You may also ask them to put an upper and lower bound on their estimate.

 

David Anderson Summer 2002-08-01